Cylinder-boring mechanism



Aug. 4, 1925. 1,548.142

- w. A. JENNINGS CYLINDER BORING MECHANISM Filed p i 14. 1922llllllll/l! I z TZM M 7 w .1 a $16M; I J 2 z M a wilmiif QM,

Patented Aug: 4, 1925.

UNITED STATES WILLIAM A. JENNI Gs, or BAYTOWN, MISSOURI.

GYLINDER-BORING MECHANISM.

Application filed April 14, 1922. Serial No. 552,739.

To aZZ whom it may concern:

Be it known that I, WILLIAM A. JEN- NINGS, a citizen of the UnitedStates, and

resident of Raytown, Jackson County, Missouri, have invented a certainnew and useful Improvement -in Cylinder-Boring Mechanism, of which thefollowing is a complete specification.

This invention relates to apparatus for the boring or reboring ofcylinders, and moreespecially of internal combustion engines, and hasfor one of its objects to produce an internal bearing for the cutterhead so that such cutter head may always be held in alinement andagainst any wobbli-ng or springing which develops into a more or lesseccentric motion and leads to an untrue boring of the cylinder.

Another object is to produce a device of this character which has anadjustable mandrel so that the device may be adapted to be used withcylinders of varying lengths.

A further object is to produce a cutter head provided with an internalbearing so constructed as to be readily adjustable to compensate forwear.

A still further object is to produce a device of the character describedof simple, strong, durable, efiicient and inexpensive construction; andin orderthat it may be fully understood reference is to be had to theaccompanying drawing, in which:

Figure 1 is a side elevation of a portion of a drill press andillustrates in section an engine block with the device of the inventioninoperative relation thereto;

Fi re 2 is a'section on the line IIII of Figure 1;

Figure 3 is an enlarged section on the line TIL-III of Figure 1;

Figure 4 is an enlarged section on the line IV-IV of Figure 1;

Figure 5 'is a section taken on-the line V-V of Figure 3;

Figure 6 is a central vertical section thimgh a modified-form of theinvention; an

Figure 7 is a section on the line VII-VII of Figure 6. i

In the said drawing, where like reference characters identifycorresponding parts in all of the figures, 1 represents the standard ofa drill press, 2 the base thereof and 3 the endof the customary drivingshaft.

Mounted upon the base in any suitable manner and preferably ofsuflicient len th to accommodate an engine block, is a bri ge member 4,formed with an opening 5 of greater diameter than the largest cylinderto be bored and axially alined with the driving shaft 3, and also formedwith a pair of inverted T-slots 6 for a purpose which will hereinafterappear.

Bolted as at 7 or otherwise secured to the underside of the bridge pieceand closing the opening 5, is a retaining member 8 in which is driven,shrunk or otherwise rigidly secured, the lower extremity of a verticalshaft 9, which. will be positioned ,as near as possible with its'axis invertical alinement with the axis of the driving shaft 3.

An engine block 10 is now disposed with one of its cylinders receivingthe stub shaft 9, and such cylinder is axially alined withsaid stubshaft and theheads of a series of long bolts 11 may now be engaged inthe T-grooves 6 of the bridge piece, and at their upper ends said boltspass through perforations; in the ends of a pair of cross barsv 12 andby means of the customary nuts on the bolts, it will be evident thatclamping pressure may be exerted on the cross bars to rigidly retain theengine block against side slip on the bridge piece, as will .be readilyunderstood. The method of securing the block, however, is unimportantprovided it is held rigidly in place. As illustrated, the en ine blockis positioned with its cran case inverted, al-

desired position of longitudinal adjustment,

depending upon the type of press and the work to be done. The upper endof the though it will be apparent that it could member 13 is formed witha tapered extremity 17 for engagement within the customary socket formedin the lower end' of the operating shaft 3 of the drill press.

The lower end of the mandrel member 14,

'is threaded as at 18 for threaded engagement with the internallythreaded upper end of a cutter head 19, it being understood in thisconnection that the internal diameter of the member it is greater thanthe diameter of the stub shaft 9.

Substantially centrally of its length the cutter head is splithorizontally as at 20 for substantially one-half of its diameter, andthe lower portion thus formed is provided with a air of ears 21 and witha central bore or aring 22, preferably,initially of slightly lessdiameter than that of the stub shaft 9. The split bearing thus formed,possesses more or less resiliency and the ears 21 will normally bespaced a slight distance apart. One of the cars 21 is formed with a pairof threaded openings and engaged in one of said openings and bearing atits end against the other ear 21 is a screw 24 formed with a socketedhead. Upon rotation of the screw in the proper direction, it will beevident that upon the application of su fiicient force, the pair of cars21 will be forced further apart and the diameter of the bearin 22 willbe correspondingly increased. ngaging the second threaded opening in theear, is the threaded extremity of a bolt 25 passing through aperforation in the other ear and formed at its end with a head forengagement by a wrench or the like. The internal bore 22 of the cutterhead is adapted to find a bearin on the shaft 9 and as said bore gradua1y increases in diameter under wear, the screw 24 will be retracted, andthe ears 21 will move toward each other due to the resiliency of thesplit ring and the diameter of the bore will be correspondinglydecreased. Whenthe entire contractive force of the split ring has beenexhausted, the bolt 25 may be rotated to draw the ears together andfurther decrease the diameter of the bore 22, as will be readilyapparent. It

- will be evident from the above that the life of the bearing 22 is thusdoubled, as it is first expanded, allowed to contract, and then forciblcontracted. 7

Running horizontally of the cutter head and at the opposite side thereoffrom the cars 21 is a slot 26 forthe reception of a bit 27, the rear endof the bit bein slightliy recessed for abutment with a soc eted ajusting screw 28 threaded in the rear end of the slot, it being evidentthat the adjustment of this screw may be used to vary the depth of thecut made by the bit. Between the rear end of the bit and the cutting endthereof, a second socketed screw 29 engages the cutter head and pressesagainst the side of the bit in such a manner as to force said bit towardthe axis of the cutter head, and a third socketed screw 30 threaded inan enlargement 31 of the cutter head engages the opposite side of thebit from the screw 29 and at a slight angle, and tends to counteract thepressure of the screws 28 and 29. It will be apparent from the abovethat the bit will be rigidly held in position against movement orspringing action in any direc tion within its socket 26, and that it maybe adjusted to vary the cut as found desirable. The stub shaft 9 isofsuch proportion as to inhibit springing movement, and as the cutter headhasa bearing on said stub shaft it will be evident that it willaccurately maintain a fixed center and that the pressure on the stubshaft will always fall in the radius of the shaft passing through thepoint of contact of the bit with the cylinder wall. It has been foundthat a split ring is unnecessary for the operation of the cutter head,because the thrust from the point of the bit is radially inward andhence applied against the rigid shaft at all times. The split ringconstruction, forming a complete bearing, is desirable to overcome anypossible tendency the bit might have to jump or dig into the cylinderwalls, but it can be dispensed with as above stated.

It will be apparent from the above that the stub shaft is depended uponto center the bit, and that even if the axis of such-stub shaft isslightly out of line with the driving shaft 3, the stub shaft willcounter-act any tendency the cutter head may have to wobble, and that,therefore, this wobbling or eccentric motion must occur in the mandreland drive shaft, between the lowermost bearing of the latter and thecutter head.

It is desirable to point out in this connection that the bridge piece tis cut away as at 5, to permit the cutter head and bit to enter therein,thus boring the entire length of the cylinder without inversion of theyengine blockor the elevation or lifting of the latter. When the engineblock is positioned with its crankcase down, it will be evident that theopening 5 is unnecessary, as the cutter head will exit into thecrankcase enlargement as will be readily understood.

In the device as illustrated in Figures 6 and 7 a modified form is shownin which: 9 illustrates the stub shaft, 14 the lower mandrel member, and10 a cylinder which is desired to bore with tapering walls.

In order to accomplish this result, the stub shaft 9 must itself betapered or, as illustrated, a tapering cone 32 may be slipped inposition on said stub shaft, it being evident that it. is immaterialwhether the cone revolves around the shaft or not, as will be readilyunderstood. It will be apparent that in this instance it is impossibleto employ a cutter head forming a complete ring, as described inconnection with Figures 1 to 5, inclusive, as in such case, the cutterhead could not slide down the ta ring cone. A cutter head 33 havin threaed engagement with the mandrel an of substantially semicircular form is,therefore, employed (see 1rliiggre 7), it being evident that a cutter ofthis character will be free for down- 3 ward travel on the cone. It isdesirable to point out in this connection that the mandrel for use inproducing a tapering or irregular boring, must be flexible or providedwith a universal joint 34, (see Figure I) in order to permit of downwardtravel of the cutter head and away from center, as otherwise the cutterhead and cone will bind, involving too great an expenditure of power toovercome the friction which would thus be produced. A bit 34 is carriedby the cutter head 33 in a similar manner to that above-described inconnection withthe cutter head 19, and in such a position that thecutting point will lie in a radius of the shaft 9 passing substantiallythrough the center of the circumference of the cutter head. It will beapparent that by varying the shape of the stub shaft or equipping itwith an irregular sleeve 32 that the cutter could be caused to operatein conformity with the stub shaft or irregular sleeve, and produce acorrespondingly irregular boring in the cylinder.

From theabove description it will be apparent that I have produced adevice of the character described, which possesses all of the featuresof advantage set forth as desirable, and while I have described andclaimed the preferred embodiment a of the same, Ireserve the right tomake all changes properly falling within the spirit and scope of theappended claims. 7

I claim 1. A cylinder boring machine comprising a drive s aft capable oflateral movement, a rigidly secured vertical stub shaft alined with thedrive shaft, and adapted to project into a cylinder to be bored, saidstub shaft having a tapered portion, a cutter head carrying mandrelattached to the drive shaft and telescoping the stub shaft, said cutterhead bearing onthe stub shaft on the cutter side of the head onlywhereby the tapered stub shaft serves as a. guide for the cutter head inits movement throu h the cylinder. 2. A cylinder boring mac e comprisinga drive shaft having therein a universal joint, a rigidly securedvertical stub shaft alined with the drive shaft, and adapted to projectinto a cylinder to be bored, said stub shaft having a tapered portion, acutter head carrying mandrel attached to the drive shaft and telescopingthe stub shaft,-said cutter head bearing on the stub shaft on the cutterside of the head only whereby the tapered stub shaft serves 'as a guidefor the cutter head in its movement through the cylinder. In witnesswhereof I hereunto aflix my signature. v WILLIAM A. JENNINGS.

